The sensor is hooked up to a serial to USB converter, and I am programming in python. The program is supposed to catch the EUI from the sensor, which is the first piece of data that comes through, however, it will not catch it reliably and I am unsure why. It sometimes catches it when I run it, and sometimes it won’t. I am writing in python and here are the libraries I am using:

import serial
import serial.tools.list_ports
import logging
from logging.handlers import TimedRotatingFileHandler
import time
import threading
import os
import re
from collections import deque


def findEUI(port, ser):
    """Find the EUI from the serial data."""
    def extractGUID(data):
        """Extract GUID from the serial data."""
        match = re.search(r'Device EUI: ([0-9A-F,]+)', data)
        if match:
            eui = match.group(1).replace(',', '')
            if eui.startswith(martin_eui_prefix):
                guid = eui_to_guid(eui)
                return guid
        return None

    startTime = time.time()
    ser.reset_input_buffer()
    attempts = 0

    while time.time() - startTime < 20:  # Timeout set to 20 seconds to capture EUI
        if ser.in_waiting > 0:
            line = ser.readline().decode('utf-8', errors='ignore').strip()
            print(f"Data read from {port}: {line}")  # Debug statement
            guid = extractGUID(line)
            if guid:
                print(f"EUI found and converted to GUID: {guid}")  # Debug statement
                return guid
        time.sleep(0.01)  # Reduce sleep time for more frequent reads
        attempts += 1
    
    print(f"Error: Unable to find EUI for {port} within 20 seconds after {attempts} attempts")
    return None

def readFromPort(port):
    """Read data from a specified serial port."""
    ser = None
    try:
        ser = serial.Serial(port, 115200, timeout=1, rtscts=True)
        print(f"Opened serial port {port}")  # Debug statement
        packetCounts[port] = 0
        logger = None

        guid = findEUI(port, ser)
        if guid:
            guids[port] = guid
            logger = setupLogger(port, guid)
        else:
            ser.close()
            return

        startTime = time.time()

        while True:
            if not ser.is_open:
                raise serial.SerialException("Serial port not open")
            while ser.in_waiting > 0:
                line = ser.readline().decode('utf-8', errors='ignore').strip()
                print(f"Data read from {port}: {line}")  # Print incoming data
                timestamp = time.time()
                holder = holder_pool.pop() if holder_pool else DataHolder(port, line, timestamp)
                holder.reset(port, line, timestamp)
                data_buffer.append(holder)
            time.sleep(0.01)  # Reduce sleep time for more frequent reads
            
            if time.time() - startTime > 60:
                raise serial.SerialException("No data received for 60 seconds")
    except serial.SerialException as e:
        print(f"Exception for {port}: {e}")
        if ser and ser.is_open:
            ser.close()
        tryReconnect(port)
    except PermissionError as e:
        print(f"PermissionError for {port}: {e}")
        time.sleep(5)  # Increase delay before retrying
        tryReconnect(port)

Here are 2 functions I wrote to try and catch the EUI, and I have even tried to increase the timeout and clear the buffer before reading in, however nothing has seemed to work.